Although the UX129 (1200MHz) band unit seems to be used successfully in several configurations with various manufacturers' controllers, Link has indicated that "... they gave up trying to determine the control coding required to make itwork...".

What is different about this band unit as compared to the others (29MHz/UX19, 54MHz/UX59, 144MHz/UX29, 220MHz/UX39, 440MHz/UX49)?

Could it be that this company had a faulty unit and just gave up?

Does anyone know the "special" controller coding to make this work that someone could provide to Link so they can add it to their software/firmware?

I can't speak to why LC gave up on the UX-129. There weren't many of these produced and I've never encountered anyone that has one (tho, that isn't saying much). The UX-129 design featured several "quirks" that were unique in comparison with the other IC-900/901 modules. The PLL chip was much more complicated and the LO featured an RIT/XIT system that used GPIO signals from the PLL chip to provide +/-7 RIT/XIT steps. See http://www.rollanet.org/~joeh/projects/ICOM_Design_Guide.pdf for an in-depth discussion of the control protocols for the different modules (note: while I *think* I understand the UX-129, I've never actually had my hands on one). The UX-129 uses the same transfer protocols as the other modules, but there are just more transfers needed. The PLL chip has 4 registers which all need to be initialized and if the RIT feature is desired, there are a series of register transfers that are needed to control the RIT circuit. This basically consists of toggling the PLL GPIO signals which connect to an up/down counter which drives a simple R-2R D/A converter that tweaks the VCO. ACC's approach was to ignore the RIT feature, but I've never seen their controllers close up.

The IC-900 service manual speaks to some of these features, but scanning data on an IC-901 was the real trick for me to figure out how the UX-129 was controlled.

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